Applied Engineering Letters

45-53

Authors: S. Grazion, V. Spiryagin, M. Erofeev, I. Kravchenko, Y. Kuznetsov, M. Mukomela, S. Velichko, A. Ašonja, L. Kalashnikova

The article presents the results of experimental estimation of the possibility of early registration of structural defects using the acoustic-emission method of control, based on the phenomenon of acoustic emission, which is the excitation of elastic vibrations of the material, caused by the formation and development of defects. To confirm the possibility of recording the processes of predestruction, such as the development of crack-like defects and plastic deformation using the acoustic-emission method of control, full-scale tests of the pressure vessel were carried out and the physical model of the shell-and-tube heat exchanger specially designed for this process was verified. It has been determined that the most informative frequency range for recording acoustic emission signals is the range of 100-200 kHz. The relationship of acoustic emission with the characteristics of defect development during plastic deformation has been studied. It was found that for reliable determination of the plastic deformation process, shared usage of amplitude and the count rate of acoustic emission is advisable.

67-73

Authors: M. Vite-Torres, M. Moreno-Ríos, A. Villanueva-Zavala, E. A. Gallardo-Hernández, L. Farfán-Cabrera, D. H. Mesa-Grajales

The phenomenon of cavitation erosion consists of the formation, growth, and collapse of bubbles in liquid media. The bubbles are responsible for the damage generated to metal and non-metal materials. Consequently, there is a pronounced degradation on the material surface, producing a scar in the impact area of the bubbles, and eventually the detachment of material. This experimental work aims to determine the performance of AISI 304 stainless steel base and coated with SiC. The SiC coating was obtained by the Chemical Vapor Deposition technique assisted by plasma. The tests were done through an ultrasonic cavitometer with a frequency of 28 kHz in an aqueous medium using tap water. According to the evidence of mass loss, results indicate that the stainless steel coated with SiC have better wear resistance than stainless steel base. In addition, failure mechanisms as cracking, plastic deformation, pits and others, were identified.

81-88

Authors: A. A. Patil, S. S. Desai, L. N. Patil, S. A. Patil

In the industry, ball bearings are the most widely used machine element. The ball materials may differ in various bearing applications. Wear of the ball and recess after a period of use is the most common cause of ball bearing failure. The present study aims to develop the artificial neural network model for assessing the wear of different ball bearing materials. A wear test method has been followed as suggested by the ASTM-G99 standard. The pin on disc apparatus was selected to conduct numerous trials. L9 array was considered to design the experiments. The factors considered for this study were load, time, and sliding speed. Based on the results obtained, ANN code was proposed to evaluate wear using numerous test parameters. The results obtained from the proposed model are nearly similar to experimental results, which would be evidence for the correctness of the model. The proposed neural network model can be used in numerous applications with given parameters.